Feasibility of Nerve Blocks in Patients Undergoing Embolization Therapy for Vascular Malformations

Abstract

Background Congenital vascular malformations cause blood to bypass the capillary bed and directly drain into the venous system. Embolization is one type of treatment and has been used for several decades to treat these malformations. Treatment-related significant pain after the embolization is not uncommon (1), and peripheral nerve blocks could reduce such pain (2). However, there is limited data on the effect of peripheral nerve blocks on postoperative pain in patients undergoing embolization therapy. This study investigates the feasibility of peripheral nerve blocks for pain control following embolization therapy in patients with vascular malformations. We hypothesize that single-injection peripheral nerve blocks can be safely performed to provide perioperative analgesia for patients undergoing embolization therapy. They will reduce morphine milligram equivalents (MME) and postoperative pain scores in patients that receive peripheral nerve blocks. Methods We performed a retrospective study of patients that received embolization therapy for a vascular malformation at Children's Hospital of Pittsburgh from 2011 to 2020. Data collected included: demographics, nerve block characteristics, perioperative opioid and non-opioid analgesia, pain scores, and hospital stay. Results 881 patients aged one day to 61 years old (Mean - 11.6 years) met the inclusion criteria. Peripheral nerve blocks were used in 5.8% of cases, with patients ranging in age from 5 to 49 years old. Out of the 51 patients who received nerve blocks, 33 (65%) received Ropivacaine 0.5%, 27 (53%) received Ropivacaine 0.2%, and 21 (41%) received clonidine. Using a linear regression model, controlling for age, sex, preoperative pain score, and duration of procedure, results showed that patients who received peripheral nerve blocks had significantly lower opioid usage (7.57 vs 12.86, p=0.006) but did not have significantly lower postoperative pain scores (2.53 vs 3.39, p=0.08). One patient from the sclerotherapy group reported sciatic nerve injury unrelated to the block. Conclusion The peripheral nerve blocks are feasible and can be used as a multimodal approach for postoperative pain control in patients undergoing embolization therapy. This report is the first study investigating peripheral nerve blocks in patients undergoing embolization therapy.